Thrust Reverser Hydraulic System Bleed Procedure [IAE]

TASK 78-30-00-870-801-A
Thrust Reverser Hydraulic System Bleed Procedure

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

1. Reason for the Job
Any time a component of the thrust reverser hydraulic system is replaced the hydraulic system must be bled to make sure that no air is in the system
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT)
No specific	1	CONTAINER 20 L - SHALLOW
No specific	1	HOSE - TRANSPARENT, SKYDROL RESISTANT
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-12-29-611-001-A	Fill the Hydraulic Fluid Reservoir with a Hand Pump
TASK 12-12-29-611-002-A	Fill the Hydraulic Fluid Reservoir with a Hydraulic Service Cart
TASK 29-14-00-614-002-A	Pressurization of the Hydraulic Reservoirs through the Ground Connector
TASK 29-14-00-614-002-A-01	Pressurization of the Hydraulic Reservoirs with the Auxiliary Power Unit (APU)
TASK 29-23-00-864-001-A	Depressurize the Green and Yellow Hydraulic Systems after Operation of the PTU
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-13-00-410-010-A	Closing of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 78-31-00-710-041-A	Operational Test of the Thrust Reverser System with the CFDS
TASK 78-31-00-710-041-A-02	Operational test of the Thrust Reverser without the CFDS and Engine Running
Hydraulic Control Unit (HCU) Bleed Valve

3. Job Set-up
Subtask 78-30-00-941-094-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than five minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 78-30-00-010-100-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Put an ACCESS PLATFORM 2M (6 FT) in position.

4. Procedure
Subtask 78-30-00-870-051-A ** ON A/C NOT FOR ALL

A. Bleed the air from the thrust reverser hydraulic system as follows

WARNING: DO NOT OPEN THE HCU BLEED VALVE WHEN THE HYDRAULIC CIRCUIT IS PRESSURIZED. REMOVAL OF THE CAP WHEN THE HYDRAULIC CIRCUIT IS PRESSURIZED CAN RESULT IN INJURY TO PERSONS.

(1) Operate the thrust reverser for 10 deploy-to-stow cycles (Ref. AMM TASK 78-31-00-710-041). Make sure that the thrust reverser doors operate smoothly.
(2) If the thrust reverser doors operate smoothly, it is not necessary to do the steps that follow.
(3) If the doors shake during opening or closing, do this Hydraulic Control Unit (HCU) bleeding procedure:
(a) Depressurize the hydraulic system (Ref. AMM TASK 29-23-00-864-001).
(b) Make sure that the hydraulic reservoirs are pressurized at 50 psi (3.45 bar) (Ref. AMM TASK 29-14-00-614-002).
(c) Bleeding of the air from the thrust reverser hydraulic system.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

1 Put a CONTAINER 20 L - SHALLOW below the HCU bleed valve to catch the hydraulic fluid.
(d) Remove the cap from the HCU bleed valve and attach one end of the HOSE - TRANSPARENT, SKYDROL RESISTANT to the valve.
(e) Put the other end of the transparent tube in the container.
(f) Slowly open the bleed valve and look for air bubbles as the fluid flows into the container.
(g) When no air bubbles are seen in the fluid flow into the container, close the HCU bleed valve.

NOTE: Use a second wrench to hold the HCU bleed valve when you turn the nut to close the valve.

(h) Operate the thrust reverser for 10 deploy-to-stow cycles (Ref. AMM TASK 78-31-00-710-041). Make sure that the thrust reverser doors operate smoothly.
(i) If the doors shake during opening or closing, repeat the HCU bleeding procedure as follows:

NOTE: Do not repeat the HCU bleeding procedure more than two times. Refer to thrust reverser trouble shooting procedure.

1 Depressurize the hydraulic system (Ref. AMM TASK 29-23-00-864-001).
2 Repeat steps (f) through (h). If reverser operates smoothly, proceed from step (j).
(j) Depressurize the hydraulic system (Ref. AMM TASK 29-23-00-864-001).
(k) Remove the transparent tube and install the cap on the bleed valve.
(l) Remove the container from below the HCU bleed valve.
(m) Make sure that the level of the hydraulic fluid in the reservoir is correct. If necessary, fill the reservoir (Ref. AMM TASK 12-12-29-611-001) or (Ref. AMM TASK 12-12-29-611-002).

5. Close-up
Subtask 78-30-00-410-082-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:27:12 UTC